Typewriting machine



May 30, 1939. w. F. HELMOND TYPEWRITING MACHINE 2 Sheets-Sheet l Filed. Jan. l5, 1936 //////T/2ZJ W rU hv.

May 30, 1939. w. F. HELMOND TYPEWRITING MACHINE Filed Jan. 15, 1936 2 Sheets-Sheet 2 Patented May 3o, 1939 ,UNITED sTTEs Y TYPEWRITING MACHINE William F. Helmond, West Hartford, Conn., as-

signor to Underwood Elliott Fisher Company, New York, N.r Y., a corporation of Delaware Application January 15, 1936, Serial No. 59,168

29 Claims.

ration to the type-bar 'structure resulting from these constantly repeated blows, resilient matel rials and structures have been substituted for the solid stop-ring. It has been found that such structures do not function satisfactorily because they do not arrest the'type-bars at the proper point to produce the desired whip action, and

- A2c, throughout the full set of type-bars, the more.

frequently used characters wear the stop-ring unevenly;l the irregularity of the type-impressionsresulting therefrom detracting from the appearance-of the work.

25 This invention discloses a stop-ring which, al-

though resilient at the moment of impact of the type-bar, quickly assumes the characteristics of a uniform, solid abutment. It is a feature of the invention that the travel ofeach type-bar, re-

30 gardless of its position in the type-bar assembly,`

` is arrested at an exact point, anda uniform whip and recoil action is obtained.` Itis a second feature that the action yls materially quieter, and less punishing to the type-bars. A third feature is that the wear on the stop-ring is. not localized, and its component parts are inexpensive and easily replaceable. U

My stop-ring is composed of a multiplicity of thin strips of substantially non-compressible, 40 non-adhesive material, such asV the resinoid Phenoli'te, hard or vulcanized -iiben plated steel, or brass, placed one on another face to face Y to form a laminated structure. vPhenolite is a r trade-name for a material made from plastic 4" phenol-condensate with `which finely divided fibrous material has been intermixed to reduce brittleness. Such plastic-phenol-condensate product has been found particularly satisfactory,

because it is non-resonant, and impervious to oil or moisture. a j' i "Phenolite or the like is commercially avail-l able in sheets of uniform thickness, and the stoprlng laminae made therefromlie smoothly and 55 atly against each other. Another' example of plastic-phenol product is the well-known Bakelite.

The laminae lie -in vnormal .contact with each other, and are non-compactly held in a vertical position against a smooth front surface of the v5 Atype-bar segment by a thin, spring-mounted,

steel facing-plate, which takes the punishment of the type-bars. An air iilm or space, estimated at .001 inch, separates the laminae by'reason of the comparatively loose mounting. It will be understood that no effort is made to control the thickness of this air iilm, it being the natural result of the method of securing the laminae.

A dust-shield, mounted flush with the type-bar segment, and having an extended flange to cover l5 the upper edges of the assembled stop-ring, is provided to prevent erasures or dust from working into the air spaces, which occurrence might impair the eiiiciency of the stop-ring.

To establish accurately the correct point at which the type-bar is arrested, the thickness of the compacted stop-ring may be held within close flimits by the use of metal shims.

The type-bar strikes the steel facing-plate of the stop-ring, which retreats from the blow, and in so doing compacts the structure of the stopring by driving the air from between the laminae in the immediate area of the blow. The stopring thus becomes increasingly resistant to compression until at a definite point, controllable by the use 'of shims as previously mentioned, the stop-ring becomes a solidly compacted structure; arresting the further travel of the type-bar and inducing the desired whip action at the typehead. 35

Other featuresl and dvantages'will hereinafter appear.

In the accompanying drawings,

- Figure l isa perspective of the invention as applied to the type-bar segment of an Underwood 40 typewriter, the stop-ring being partially in s ection to illustrate the laminated construction.

Figure `2 is a sectional elevation, substantially enlarged, of the construction of ,Figure 1, representing the condition of the vstop-ring at the moment of contact of the type-bar.

Figure 3 is a view similar to Figure 2, illustrate ing the arrest of the type-bar bythe compacted stop-ring, and diagrammat'ically illustrating the 5o e whipfof the type-head to the. platen.

Figure 4 is a Ymagni'ed section of the stop,

,ring of Figure 3. y Figure 5 is a magnified sectional view of the .stop-ring 'in repose. 55

Figure 6 is a' perspective, disassembled view of the complete stop-ring.

Figure 7 is a section taken through 1 1 of Figure 1.

Figure 8 is a magnified view of a modified form of construction.

Figure 9 is a perspective and section of a lamina as employed in Figure 8.

A type-bar segment I5, having a smoothly machined front surface I6, is secured to a member I1 of a typewriting-machine frame. Slots I8, cut through a thickened lower portion 20 of the segment, accommodate type-bars 2 I, FigureV 2, which are pivotally mounted on a fulcrum-wire 22, and arranged to be swung, in the usual manner, to cause type-heads 23 to come vinto printing-position against a platen 24. A type-guide 25, Figure 1, co-operates with the upper portion of the typebars 2| to assure the correct printing-position. Floating-frame guide rollers 26 are journaled in spring-brackets 21, said brackets being secured to the segment, as by screws 28, at each side of a stop-ring 30. The stop-ring 30 is wider than the usual solid abutment, and therefore the brackets 21 are preferably inwardly offset, as shown in Figure l, so that the rollers 2B may be in co-operative alignment with standard guideslots provided in tongues (not shown) secured to the floating-frame of an Underwood machine, all as described in my Patent No. 1,571,946, dated February 9, 1926.

The stop-ring 30 is composed of laminae 3I, stamped out of thin sheets of Phenolite, ber or metal. There are preferably at least four lam'- inae, but, as shown in the drawings, a larger number may be used. The laminae are of uniform width, preferably fig". They may be concentrically arcuate with the segment I5, and formed with their ends parallel to the upper edge of the said ring, as shown in Figure 6. It is important that each lamina be of uniform thickness throughout, but it is not essential that all of the laminae composing the stop-ring be -of equal thickness, or of the same material.

Phenolite, as it is readily obtainable in sheets of closely uniform thickness, and as it does not crimp or develop a wavy surface during handling, has been found to be superior to other materials for the purpose.

A metal plate 32, Figures 1 and 6, preferably of thinspring-steel, concentric with the laminae, and of substantially equal width, is employed to take the punishment of the type-bars, and to hold the laminae 3| non-compactly in position against the front surface I6 of the segment I5. The plate 32 may be made in a single operation by a combination blanking, piercing or forming die. Flanges 33 disposed at the ends of the plate 32 and connected to the latter overlie the upper surface of the segment I5, thus to prevent the lateral displacement of the laminae, and to protect the edges thereof against damage or the entry of clust. Mounting tongues 34, Figure 6, at the top and bottom edges'of the plate 32, have inwardly offset portions 34 and are punched or drilled with holes 35. As shown in Figure 7, the depth of the offset 34a is less than the overall thickness of the assembledv stop-ring, and the said tongues are parallel to the surface ofthe facing-plate 32 and the face I6 of the segment.

Lugs 36, Figure 6, are also formed at the bottom edge of the plate 32, the said lugs being of greater length than the over-all thickness of the stop-ring 30. Holes 31, Figure 1, are provided in the segment I5 to receive the ends of the lugs 36.

An arcuate dust-shield 38, preferably of metal, is formed with a rear surface 4U, to lie in close contact with the segment-surface I6 and with a forwardly-extending flange 4I, to overlie the laminae 3| and a portion of the facing-plate 32 in spaced relationship therewith, as shown in Figures 4 and 5. The ange 4I is made wide enough to protect the relaxed stop-ring against the entry of dust and erasures, but not to extend beyond the forward edge 0f the facing-plate when the stop-ring is fully compacted during operation.

The stop-ring is assembled, preparatory to mounting, by placing the laminae one on another, within the confines ofthe flanges 33, the mounting tongue-offsets 34a and the lugs 36 of the plate 32, these members forming a skeleton pocket in which the laminae are loosely held. The assembled stop-ring isV held in position against the segment-face I6 by screws 42, which l have a shouldered portion 43 which sldably passes through the mounting holes 35. The facing-plate 32 yieldably confines the laminae by the action of spring-washers 44 interposed be? tween the mounting tongues 34 and the heads of th-e screws 42. The dust-shield 38 is securely held by the upper screws 42, which pass through holes 45 at the ends of the said shield, and conne the latter closely against the segment-surface I6 by the shoulders 43 vof the screws.

The shouldered portions 43 act as a positive means 0f gaging the depth of insertion of the screws 42. As shown in Figure 7, the shoulders 43 of the lower screws are lengthened to compensate for the thickness of the dust-shield surface 40, and the facing-plate 32 thus confines the laminae 3I with equal tension, 'Ihe springwashers 44 are insucient to hold the stop-ring structure in'closely compacted form. The use of four mounting screws 42 and spring-washers 44 has been found sufficient to equalize the pressure exerted by the facing-plate 32 on the laminae 3l.

To arrest the type-bars at the correct point, measured by the distance between the type-head 23 and the platen 24, at the point of arrest, and thus insure the proper whip action, the overall depth of the compacted stop-ring must be held within accurate limits. Because of the practical difculty in obtaining Phenolite or other such synthetic material in extremely thin sheets, a metal shim 46, preferably of brass, is inserted generally between the facing-plate 32 and the first lamina. Such shims are readily procurable in accurately gaged thicknesses, and it is thus practicable to maintain exact standards.

A cross-section of the assembled, relaxed, stopring, seen in magnified view in Figure 5, discloses that the laminae are separated by an air film 41. Experimental data and measurements indicate that the film between each lamina is approximately .001 inch in thickness, and is substantially uniform over the entire area of the stop-ring.v

As the type-bar 23 strikes the facing-plate 32 during operation, the latter, being free to withdraw from the blow by the yieldable manner in which it is mounted, drives the laminae'rearwardly, compacting them into a substantially solid structure as shown in magnified view in Figure 4, by. forcing a large portion of the air out from between the laminae. The cushioning effect of this air movement absorbs much of the impact of the type-bar and considerably lessens the noise of the contact. However, as each typebar strikes the stop-ring with the same force, the

'stop-ring is compacted in the same degree regardless of the position of the type-bar in the type-bar segment,` and each type-headwhips evenly to the platen. The whip action is diagrammatically shown in Figures '2 and 3, the latter showing the stop-ring compacted. from the blow, and, in dotted lines, illustrating the extent of the whip.

Figures 8 and 9, in enlarged views, show a modified construction of the stop-ring 30, vin

which the laminae 3| are made up of thin iron or steel plates, on which a thin, even coating 48 of lead, cadmium or other metals is deposited, as\by electro-plating. The preferred thickness of the said coating is .005 inch. Lead is preferred, because it is itself non-resonant, and possesses excellent sound-deaderiing qualities when thickness of the assembled stop-ring. At each end of the shim 46, the flange or tab 33 may be formed at right angles thereto, to overlie theupper edge of the segment I5, as shown in Figure 1 l The tabs 33 secure the shim 46 against any possibility of sliding 'laterally around the stop-ring, when the machine is being handled during shipping, as the contact of one or the other of said tabs with the segment prevents any appreciable movement of the shim in either direction. The tabs' 33 also overlie the laminae 3|, and therefore also prevent the latter from becoming detached, even though the machine be held upside down in the shipping case. It will beunderstood that the lamina immediately adjacent to the facing-plate 32 may be formed with flanges similar to 33, as shown on the shim 46, and for the same purpose.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim: 1. In a typewriting machine, the combination with type-bars and a segment or-frame on which theyare pivoted, of a stop-ring to arrest the travel of the said type-bars on their printing 4 strokes, said stop-ring including a multiplicity of laminae. non-compactly held against the surface of the said segment by yieldable means.

2. In a typewriting machine, the combination with type-bars and a segment or-frame on which they are pivoted, of a stop-ring to arrest the travel of the said type-bars on their printing strokes, said stop-ring including a multiplicity of laminae, held against the surface of the said segment by means including a wear-resisting facing-plate to take the punishment of the typebars, said plate having offset tongues, and means (Jo-operating with said tongues yieldably to hold said plate in contact with said laminae.

3. In a typewriting machine, the combination with type-bars and a segment or frame on which they are pivoted, of a sound-deadening stop-ring yto arrest the travel of the said type-bars on their printing strokes, said stop-ring including a multiplicity of non-resonant laminae, non-.compactly held against the surfaceof Isaid segment by a yieldably mounted Wear-resisting facing-plate.

4. In a typewriting machine havinga plurality of type-bars pivotally mountedI in a segment or frame, a stop-ring interposed in the path of said 4 v type-bars to arrest the travel thereof on the printing strokes, said stop-ring including a mulprinting strokes, said stop-ring including a mull tiplicity of metallic laminae having a non-resonant coating, means for non-compactly holding said laminae against the surface of said segment,

and means protecting against the entry of detritus between said laminae.

6. In a typewriting machine having a plurality of type-bars pivotally mounted in a segment or frame, astop-ring interposed in the path of said type-bars to arrest the travel thereof on the printing strokes, said stop-ring including metallic laminae non-compactly lceld against the surface of said segment, said lax., :ae being electroplated, and means for protecting against the entry of detritus between said laminae.

'7. In a typewriting machine, the combination with type-bars and a segment or frame on which they are pivoted, of a stop-ring to arrest the travel of the said type-bars on their printing strokes, said stop-ring including a multiplicity of laminae, held against the surface of the said segment by means including a wear-resisting facing-plate to take the punishment of the typebar's, said facing-plate loosely confining the said laminae against the segment by means including flanges disposed over the tops of said laminae and connected to said facing plate, inwardly turned laminae-seating lugs on said plate, in-

wardly offset mounting tongues on said plate,-

headed screws passing through said tongues, in slidable relationship therewith, into said segment, and spring-washers interposed between said tongues and the heads of said screws.

8. In a typewriting .machine, the combination with type-bars and a segment or frame on which they are pivoted, of a strip-ring to arrest the travel of the said type-bars on their vprinting strokes, said stop-ring including a multiplicity of laminae, held against .the surface of the said segment by means including a wear-resisting facing-plate to take the punishment of the typebars, said facing-plate loosely conning the said laminae against the segment by means including flanges disposed over the tops of said laminae .and connected -to said facing-plate, inwardly turned laminaeseating lugs on said plate, inwardly offset mounting tongues on said plate, headed screws passing through said tongues, in slidable relationship therewith, into said segment, spring-washers interposed between said tongues and the heads of said screws, and means forgaging the depth of insertion of said screws into said segment.

9. In a typewriting machine, the combination with type-bars and a segment or frame on which they are pivoted, of a. stop-ring to arrest the travel of the said type-bars on their printing strokes, said stop-ring including a multiplicity of laminae, held against the -surface of the said segment "by means including a wear-resisting facing-plate to take the punishment of the typebars, said facing-plate loosely confining the said laminae against the segment by means including anges disposed over the tops of said laminae and connected to said facing-plate, inwardly turned laminae-seating lugs on said plate having a length in excess of the thickness of the assembled stop-ring, said segment arranged to accommodate said excess length, inwardly offset mounting tongues on said plate, headed screws passing through said tongues, in slidable relationship therewith, into said segment, and spring-washers interposed between said tongues and the vheads of said screws.

10. The combination with type-bars and a segment or frame in Which they are pivotally mounted, said segment having a smoothly machined front surface, of a stop-ring including a wear-resisting plate, a multiplicity of flatsurfaced laminae interposed between said plate and said segment, and means `yieldably holding said laminae therebetween, said laminae arranged to be compacted against said segment by the blow of the said type-bars.

l1. In a typewriting machine, the combination with type-bars and a segment on which they are pivoted, of a sound-deadening stop-ring comprising a multiplicity of laminae, a metal facingplate holding said laminae in such manner as to permit the free entry of a cushioning air-film therebetween, and means securing said plate to said segment to permit the rearward motion of said plate under the impact of the said type-bars and thus partially to expel the air from between the said laminae.

12. In a typewriting machine, the combination with type-bars having type-heads, and a segment or frame in which they are pivoted, of

means to quietly arrest the travel of the typebars at a definite point before printing, whereat the type-head, by accumulated momentum springs to the platen to make the impression, said means comprising a stop-ring formed by a multiplicity of laminae individually loosely assembled on said segment or frame sc as to initially yield one after the other under the impact of the said type-bars and thereby finally compact into a non-yielding abutment.

13. In a typewriting machine, the combination with type-bars and a segment on which they are pivoted, of a sound-deadening stop-ring cornprising a multiplicity of laminae, and a metal facing-plate holding said laminae in such manner as to permit cushioning air-film therebetween.

14. The combination-with type-bars and a frame in which they are pivotally mounted, of a type-bar stop-ring including a multiplicity of laminae detachable from` one'ancther, and means mounting said laminae non-compaetly face to face on said frame with the face of one lamina substantially against a surface of said frame, said surface finally receiving the type-bar impact through said laminae as the latter become compacted under said impact.

l5. In a typewriting machine, the combination with type-bars and a segment or frame on which they are pivoted, of a laminated stop-ring to arrest the travel of the said type-bars on their printing strokes, said stop-ring being arranged and mounted so that its laminae are normally loose and non-compacted but become compacted facewise toward one another and against the surface of the said segment when arresting the type-bar strokes.

16. The combination with type-bars and a segment or frame in which they are pivotally mounted, of a stop-ring including a multiplicity of laminae detachable from one another, said segment having a stop-ring-supporting surface, and means loosely mounting said laminae face to face and against said surface.

17. In a typewriting machine, the combination with type-bars and a segment or frame on which they are pivoted, of a loosely integrated nonresonant stop-ring formed by a multiplicity of laminae individually loosely assembled on said segment or frame so as to be pressed serially by the blow of the said type-bars and compacted into a non-yielding abutment of denite thickness.

18. In a typewriting machine, the combination with type-bars having a segmental mounting, of a set of buffer-plates superposed in substantially loose face to face assembly to constitute a slightly yieldable non-resonant stop for arresting the type-bars at the printing operation, said assembly being susbtantially loosely maintained against a surface of said mounting, said surface nally receiving the type-bar impact.

19. In a typewriting machine, the combination with type-bars having a segmental mounting, of a multiplicity of buiTer-plates loosely superposed face to face in non-compacted assembly to constitute a slightly compactible and therefore slightly yieldable stop assembly for arresting the type-bars at the printing operation, said plates being made of non-'resonant hard fibrous material, said assembly being loosely maintained against a surface of said mounting, said surface finally receiving the type-bar impact.

20. In a typewriting machine, the combination with type-bars having a segmental mounting, of a multiplicity of buier-plates loosely superposed face to face in non-compacted assembly to constitute a slightly compactible and therefore slightly yieldable stop for arresting the type-bars at the printing operation, said plates being made, for durability and non-resonance, of hard sheet-metal thinly coated with a softer metal, said assembly being loosely maintained against a surface of said mounting, said surface finally receiving the type-bar impact.

2l. In a typewriting machine, the combination with type-bars and a segment on which they are pivoted, of a sound-deadening stop-ring for accurately intercepting the type-bars just before printing, including a multiplicity of laminae, and means loosely mounting said laminae face to face on said segment in such manner as to permit cushioning air-film therebetween.

22. In a typewriting machine, the combination with type-bars and a segment on which they lare pivoted, of a sound-deadening stop-ring for accurately intercepting the type-bars just before printing, including a multiplicity of laminae, and means loosely mounting said laminae face to face on said segment in such manner as to permit cushioning air-film there-between, said laminae including an outer wear-resisting face-plate of metal and a multiplicity of inner laminae, interposed between said face-plate and segment and made of non-metallic material that is substantially incompressible under the type-bar blows,

23. In a typewriting machine, the combination with type-bars and a segment on which they are pivoted, of a sound-deadening stop-ring for accurately intercepting the type-bars just before printing, including a multiplicity of laminae, and means loosely mounting said laminae face to face on said segment in such manner as to permit cushioning air-film there-between, said laminae including an outer wear-resisting face-plate of 'stops mounted on the ends of the cage for retaining the filler plate or plates against endwise displacement.

25. A type bar abutmentcomprising a cage including a front striker plate, one or more noisereducing filler plates mounted in said cage, and stops mounted on the cage for co-operation with the ller plate' or plates to retain the latter against endwise displacement.

26. In a key-operated machine, the combination with a fixed stop and a striking member, of a multiplicity of thin flexible laminations forming a pack which is backed against said stop and is provided with a cap struck by said member, said pack being caused by the impact of said member to pack `rnore closely against said fixed strokes, said stop-ring including a multiplicity of thin flexible laminae, held lightly together against the surface of the said segment by yield able means.

28. In a typewriting machine, thecombination with type-bars having type-heads, and a.' fixed segment or mount in which they are pivoted, of means to quietly arrest the type-bars at a definite point before printing, whereat the type-head by momentum springs to the platen to make the impression, said means comprising a stop-ring formed by a multiplicity of thin ,flexible laminae lightly packed on said segment or mont so as to yield one after another under the impact of any of said, type-bars and thereby finally compact against said segment to form a non-yielding muting abutment.

29. In' a. typewriting machine, the combination with type-bars and a fixed segment or mounton which they are pivoted, of a laminated stop-ring co-operatingwith said fixed segment to arrest said type-bars at their printing strokes, said laminae being thin and exible but normally loose and non-compacted, and' being compressible facewise against one another and against the surface of said segment when arresting the typebars, for muting the type-bar blows.

WILLIAM F. HELMOND. 

